EP1687937B1

EP1687937B1 - Diagnostic system for a modular fieldbus board

Info

Publication number: EP1687937B1
Application number: EP04768621A
Authority: EP
Inventors: Gunther Rogoll; Renato Kitchener
Original assignee: Pepperl and Fuchs SE
Current assignee: Pepperl and Fuchs SE
Priority date: 2003-10-03
Filing date: 2004-09-24
Publication date: 2007-10-24
Anticipated expiration: 2024-09-24
Also published as: DE602004009707T2; US7698103B2; US20070124111A1; GB0323178D0; EP1895711B1; EP1687937A1; EP1895711A3; CN100492997C; US20100185415A1; CN1890922A; EP1895711A2; DE602004009707D1; WO2005041484A1; ATE376732T1

Abstract

A diagnostic system for a modular fieldbus board carrying a number of fieldbuses connected to a bulk power supply, comprising a monitoring transceiver means adapted in use to one or more of the number of fieldbuses by means of two or more common mode and/or differential mode signal injection and/or signal detection points, which points are dispersed between the bulk power supply and the fieldbus trunk, such that the monitoring transceiver means can detect one or more fieldbus physical layer characteristics between two of the two or more of said points.

Description

This invention relates to a modular fieldbus board with a diagnostic system, for use particularly to monitor fieldbus physical layer characteristics on a modular fieldbus board carrying a number of fieldbuses.
Modular fieldbus boards and the fieldbus systems to which they are attached occasionally suffer from faults which lead to a reduction in performance, or a complete failure. There is currently no known way to monitor the performance of the components of a modular field bus board to detect and diagnose faults and failures. As such, characteristics of performance which are indicative of potential faults are not detected, and faults and failures which actually occur cannot be easily identified for rectification.
It is know to provide diagnostic systems for bus structures. For example, US 5831805 in the name of LOTOCKY DAN ET AL discloses a basic diagnostic circuit applied to a node in a bus structure which detects if sufficient power is being supplied from a local power supply to physical connections within the node. If the power is not sufficient the disclosed circuit disables a clock signal to those physical connections in order to save power.
In US-A-5831805 there is disclosed a local power failure detection and clock disabling circuit operating within a node coupled to a bus structure. The node includes multiple ports and physical connections for supporting multiple applications. Each physical connection serves as a bus transceiver for receiving and transmitting communications over the bus structure. The node includes a local power supply and a clock signal which is provided to each of the physical connections within the node. A detection circuit is coupled to the local power supply for detecting whether or not a sufficient level of power is being supplied from the local power supply. The clock signal is always provided to a master physical connection within the node, which is responsible for repeating communications across the bus structure. The master physical connection draws power from the backup power supply source when the local power supply is not supplying a sufficient level of power. When the detection circuit has detected that the local power supply is not supplying a sufficient level of power, the clock signal is disabled to all of the physical connections within the node, except the master physical connection, in order to minimize power consumption of the node. The local applications coupled to the node are also disabled when a sufficient level of power is not supplied from the local power supply. When the detection circuit detects that the local power supply is again supplying power at a sufficient level, the clock signal is reenabled to all of the physical connections within the node and the local applications are also reenabled.
In US-A-5757265 there is disclosed a field bus system in which transmission ability of the system can be maintained even if communication error occurs due to noises or failure of a transmission line. The system can be easily shifted at a lower cost from a conventional system to the field bus system without degrading the high reliability thereof. The transmission line is constituted by a multiple-cable transmission line having at least three transmission cables. An external power supply supplies power to field devices through a pair of transmission cables of the multiple-cable transmission line. The field devices are connected to the transmission cables through a transmission line switching unit constituted by a plurality of rectifier elements, so that the field devices are supplied with current flowing in one predetermined direction when any of the pairs of transmission cables is selected. The external power supply monitors a failure of a currently used pair of transmission cables and, upon detection of failure of the currently used pair of transmission cables, the failed pair is replaced by a normal pair of transmission cables such that the field devices are continuously supplied with power.
In US-A1-2002/169582 there is disclosed a field device coupleable to a fieldbus process communication loop, the device comprising: a power module coupleable to the loop to power the device with energy received from the loop, a fieldbus loop communicator coupleable to the loop, and adapted to bi-directionally communicate over the loop, a controller coupled to the fieldbus loop communicator, diagnostic circuitry coupled to the controller and operably coupleable to the loop, the diagnostic circuitry adapted to measure a loop-related parameter, and wherein the controller provides diagnostic information based upon the loop-related parameter.
In WO-A-02/099663 there is disclosed an intrinsically safe field bus system comprising a field bus, a power source, a terminating resistor and at least one field bus device connected to the field bus. The power source is connected to a first end of the field bus and the terminating resistor terminates the field bus on the other end. The power source generates a periodic alternating signal, has a reactance as a terminating resistor and a unit for control and adjustment of the power source according to the input impedance (ZBus) of the field bus. The field bus input current (IBus) is kept constant when the input impedance (ZBus) in a first range of operation (I) is smaller than the wave impedance (ZW) of the field bus line, and the field bus input voltage (UBus) is adjusted to a constant maximum voltage (Umax) and the field bus input current (IBus) is adjusted according to the input impedance (ZBus) if the input impedance (ZBus) exceeds the value of the wave impedance (Zw) in a second operating range (II).
In DE-A-10104908 there is disclosed an electronic device for permanent monitoring electrically measurable states or values of bus systems, such as Profibuses, field buses, etc., after the bus has been installed, with two bus conductors, a comprehensive power supply and data bus, that connects a bus master and a bus slave together. Accordingly the device samples a number of connections of the electrically measurable bus conductors using a permanent circuit connection for voltage or current measurement, testing earth connection testing the quality of the bus conductors and the signals they carry. The current testing of bus systems is based on connection of measurement meters and multimeters after installation to test the bus system and to correct any faults.
What is needed is a diagnostic system for a modular field bus board carrying a number of fieldbuses connected to a bulk power supply, comprises a monitoring transceiver means, such that the monitoring transceiver means can detect one or more fieldbus physical layer characteristics.
The present invention is intended to overcome some of the above problems.
Therefore, according to the present invention a modular fieldbus board comprising a number of fieldbuses connectable in use to a bulk power supply, is characterised in which: the modular fieldbus board is provided with a diagnostic system comprising a monitoring transceiver means connected to one or more of the number of fieldbuses, in which each connection to a fieldbus comprises one or more common mode and/or differential mode signal injection points and one or more corresponding common mode and/or differential mode signal detection points, in which said points are dispersed between the points at which the fieldbus is connectable to the bulk power supply and to a fieldbus trunk, and in which the monitoring transceiver means is adapted to detect one or more fieldbus physical layer characteristics between any signal injection point and any signal detection point.
Preferably the field bus physical layer characteristics which are monitored comprise one or more of: over/under termination, noise/ripple level, signal level, signal bias, signal jitter, signal ringing, signal distortion, signal attenuation, cross talk, unbalance, and earth leakage.
In a preferred construction the modular fieldbus board can carry hardware and the monitoring transceiver means can also be adapted to detect one or more characteristics of hardware disposed between any signal injection point and any signal detection point. The hardware can be bulk power supply connections, power supply converters, power supply conditioners and fieldbus trunks. The characteristics to be monitored can comprise one or more of: voltage, short circuit, hardware module failure, quiescent current, and rate of charge.
The monitoring transceiver means can also be adapted to gather received data and produce one or more of: Fourier analysis, trending analysis, and data logging.
Preferably the monitoring transceiver means may be adapted to provide an alarm in the event that received data indicates that one or more of pre-determined failures has occurred on any of the fieldbuses.
In one construction the monitoring transceiver means can be provided with a first digital and/or an analogue interface, such that diagnostic data detected and/or alarms generated by the monitoring transceiver means in use can be transmittable to a digital or analogue device operated by a user, and such-that user operating commands can be receivable from a digital or analogue device operated by a user.
Alternatively, or in addition to the first interface, the monitoring transceiver means can be provided with visual means adapted to display diagnostic data detected and/or alarms generated in use.
In addition, the monitoring transceiver means can be provided with a second digital and/or an analogue interface, such that diagnostic data detected and/or alarms generated by the monitoring transceiver means in use can be transmittable to other associated diagnostic systems, and such that data can be receivable from other associated diagnostic systems.
Preferably the monitoring transceiver means can be releasably connected to the fieldbus board, and it can be connectable in use by a bulk power supply.
In one construction one or more of the signal injection points and/or one or more of the signal detection points can be disposed within the hardware referred to above.
Preferably each of the one or more fieldbuses can comprise a point at which it is connectable to a the bulk power supply, a power supply converter, a power supply conditioner and a point at which it is connectable to a fieldbus trunk.
On each of the one or more fieldbuses a first common mode signal injection and/or signal detection point can be disposed between the point at which the fieldbus is connectable to a bulk power supply and the power supply converter, a second common mode signal injection and/or signal detection point can be disposed between the power supply converter and the power supply conditioner, a third a common mode signal injection and/or signal detection point can be disposed between the power supply conditioner and the point at which the field bus is connectable to a field bus trunk, and a differential mode signal injection and/or signal detection point can be disposed between the third common mode signal injection and/or signat-detection point and the point at which the fieldbus is connectable to a fieldbus trunk.
In addition, in a preferred construction a fourth common mode signal injection and/or signal detection point can be disposed within the power supply converter, and a fifth common mode signal injection and/or signal detection point can be disposed within the power supply conditioner.
The invention can be performed in various ways, but one embodiment will now be described by way of example and with reference to Figure 1, which shows a diagrammatic display of a modular fieldbus board according to the present invention.
As shown in Figure 1, a modular fieldbus board 15 comprising a backplane, on which is mounted any number of fieldbuses 8a, 8b and 8n in series and a monitoring transceiver means 17, (which may also be described by those in the art as a segment autonomous diagnostic system). (The fieldbuses comprise at least fieldbuses 8a and 8b, while 8n diagrammatically signifies any number of further fieldbuses, and is therefore shown in hashed lines.)
The modular fieldbus board 15 is shown in an in use configuration and as such the field buses 8a to 8n are connected to bulk power supply 1, and each comprise a power supply converter 3 and a power conditioner 5.
The monitoring transceiver means 17 is provided with a first digital interface, signified by arrow 16, which in use interfaces with a user operated digital control system. Further the monitoring transceiver means 17 is provided with a second digital interface, signified by hashed arrow 19, which in use can interface with similar diagnostic systems provided on associated modular fieldbus boards (not shown).
The monitoring transceiver means 17 is further provided with visual means (signified by arrows 14) which can provide information and warning signals direct to users.
The monitoring transceiver means 17 is connected to each fieldbus 8a to 8n by first common mode signal injection and detection point 2 between the bulk power supply 1 and the power supply converter 3, by second common mode signal injection and signal detection point 4 between the power supply converter 3 and the power supply conditioner 5, by third a common mode signal injection and signal detection point 6 between the power supply conditioner 5 and the field bus trunk (not shown), and by differential mode signal injection and signal detection point 7 between the third common mode signal injection and signal detection point 6 and the fieldbus trunk (not shown).
In addition, the monitoring transceiver means 17 is connected to each fieldbus by fourth common mode signal injection and signal detection point (not visible, but indicated by connection arrow 9) which is disposed within the power supply converter 3, and by fifth common mode signal injection and signal detection point (again, not visible but indicated by connection arrow 11) disposed within the power supply conditioner 5.
The monitoring transceiver means 17 can monitor for fieldbus physical layer characteristics including over/under termination, noise/ripple level, signal level, signal bias, signal jitter, signal ringing, signal distortion, signal attenuation, cross talk, unbalance, and earth leakage, between any of the above described points.
In addition, the monitoring transceiver means 17 can monitor for voltage, short circuit, hardware module failure, quiescent current, and rate of charge, between any of the above described points.
The monitoring transceiver means 17 is programmed to compile received data in use and produce Fourier analysis, trending analysis, and data logging.
Further, the monitoring transceiver means 17 is programmed to provide an alarm, either via the interfaces 16 or 19, or the visual means 14, in the event that data in use indicates one or more of pre-determined failures or the one or more fieldbuses. The indications of failures in the data are pre-programmed into the transceiver 17.
Thus, the modular fieldbus board can provide many types of information on its performance and on any potential failures to a user.

Claims

A modular fieldbus board (15) comprising a number of fieldbuses (8a to 8n) connectable in use to a bulk power supply (1), characterised in which: the modular fieldbus board (15) is provided with a diagnostic system comprising a monitoring transceiver means (17) connected to one or more of the number of fieldbuses (8a to 8n), in which each connection to a fieldbus (8a to 8n) comprises one or more common mode and/or differential mode signal injection points (2, 4, 6, 7, 9 or 11) and one or more corresponding common mode and/or differential mode signal detection points (2, 4, 6, 7, 9 or 11), in which said points (2, 4, 6, 7, 9 or 11) are dispersed between the points at which the fieldbus (8a to 8n) is connectable to the bulk power supply (1) and to a fieldbus trunk, and in which the monitoring transceiver means (17) is adapted to detect one or more fieldbus physical layer characteristics between any signal injection point (2, 4, 6, 7, 9 or 11) and any signal detection point (2, 4, 6, 7, 9 or 11).
A modular fieldbus board (15) as claimed in Claim 1 in which the fieldbus physical layer characteristics comprise one or more of: over/under termination, noise/ripple level, signal level, signal bias, signal jitter, signal ringing, signal distortion, signal attenuation, cross talk, unbalance, and earth leakage.
A modular fieldbus board (15) as claimed in Claim 1 or 2 in which the modular fieldbus board (15) carries hardware (3, 5) and in which the monitoring transceiver means (17) is also adapted to detect one or more characteristics of hardware (3, 5) disposed between any signal injection point (2, 4, 6, 7, 9 or 11) and any signal detection point (2, 4, 6, 7, 9 or 11).
A modular fieldbus board (15) as claimed in Claim 3 in which the one or more characteristics of hardware (3, 5) comprise one or more of: voltage, short circuit, hardware module failure, quiescent current, and rate of charge.
A modular fieldbus board (15) as claimed in Claim 4 in which the monitoring transceiver means (17) is adapted to gather received data and produce one or more of: Fourier analysis, trending analysis, and data logging.
A modular fieldbus board (15) as claimed in any of the preceding Claims in which the monitoring transceiver means (17) is adapted to provide an alarm in the event that received data indicates that one or more of pre-determined failures has occurred on any of the fieldbuses (8a to 8n).
A modular fieldbus board (15) as claimed in any of the preceding Claims in which the monitoring transceiver means (17) is provided with a first digital and/or an analogue interface (16), such that diagnostic data detected and/or alarms generated by the monitoring transceiver means (17) in use are transmittable to a digital or analogue device operated by a user, and such that user operating commands are receivable from a digital or analogue device operated by a user.
A modular fieldbus board (15) as claimed in Claim 7 in which the monitoring transceiver means (17) is provided with a second digital and/or an analogue interface (19) such that diagnostic data detected and/or alarms generated by the monitoring transceiver means (17) in use are transmittable to other associated diagnostic systems, and such that data is receivable from other associated diagnostic systems
A modular fieldbus board (15) as claimed in any of Claims 6 to 8 in which the monitoring transceiver (17) means is provided with visual means adapted to display diagnostic data detected and/or alarms generated in use.
A modular fieldbus board (15) as claimed in any of the preceding Claims in which the monitoring transceiver means (17) is releasably connected to the fieldbus board (15).
A modular fieldbus board (15) as claimed in any of the preceding Claims in which the monitoring transceiver means (17) is connectable to a bulk power supply (1).
A modular fieldbus board (15) as claimed in any of the preceding Claims 3-11 in which one or more of the signal injection points (2, 4, 6, 7, 9 or 11) and/or one or more of the signal detection points (2, 4, 6, 7, 9 or 11), are disposed within said hardware (3, 5).
A modular fieldbus board (15) as claimed in any of the preceding Claims 3-12 in which each of the one or more fieldbuses (8a to 8n) comprises a point at which it is connectable to a bulk power supply (1), a power supply converter (3), a power supply conditioner (5) and point at which it is connectable to a fieldbus trunk.
A modular fieldbus board (15) as claimed in Claim 13 in which in each of the one or more fieldbuses (8a to 8n) a first common mode signal injection and/or signal detection point (2) is disposed between the point at which the fieldbus is connectable to a bulk power supply (1) and the power supply converter (3), in which a second common mode signal injection and/or signal detection point (4) is disposed between the power supply converter (3) and the power supply conditioner (5), in which third a common mode signal injection and/or signal detection point (6) is disposed between the power supply conditioner (5) and the point at which the fieldbus is connectable to a fieldbus trunk, and in which a differential mode signal injection and/or signal detection point (7) is disposed between the third common mode signal injection and/or signal detection point (6) and the point at which the fieldbus is connectable to a fieldbus trunk.
A modular fieldbus board (15) as claimed in Claim 14 in which a fourth common mode signal injection and/or signal detection point (9) is disposed within the power supply converter (3), and in which a fifth common mode signal injection and/or signal detection point (11) is disposed within the power supply conditioner (5).